#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>
#include <sstream>
#include <iostream>
#include <string>
#include <cstdio>
#include <cmath>

using namespace std;

int main() {

	double A, B;
	cin >> A >> B;
	cout << 50*(int)A + (int)((50.0*A) / (0.8 + 0.2*B) + 1e-9) << endl;


	return 0;
}